1. Field of the Invention
The present invention relates to a control device which performs warning or running control on the basis of a distance between one's own vehicle and a preceding vehicle.
2. Description of the Related Art
Until now, some devices are developed, which detect a distance between one's own vehicle and a preceding vehicle by using a radar, and which, on the basis of the distance between the two vehicles, perform warning or running control by using a throttle or brakes. For example, in Japanese Laid-Open Patent Application No. 60-131327, a running control device is described, which detects a distance between one's own vehicle and a preceding vehicle, and calculates a safety distance between two vehicles according to the speed of one's own vehicle. The control device detects a change of a distance between two vehicles exceeding a specified value, and outputs a vehicle speed holding signal for a specified time length. The control device calculates a rate of acceleration or deceleration for adjusting the speed of one's own vehicle so as to make the distance between two vehicles to be a safety distance between two vehicles. The control device changes a throttle valve opening according to the rate of acceleration or deceleration so as to hold the vehicle speed at a speed at which the vehicle was running just before the distance between two vehicles changes if the speed of a preceding vehicle is higher than the speed of one's own vehicle by a value exceeding a given value when a vehicle speed holding signal is inputted or the inputting is finished.
In the prior art devices, as position data of a preceding vehicle, only the distance between two vehicles is detected, and the running control is performed on the basis of the distance between two vehicles. Therefore, when a stop lamp of the preceding vehicle is lighted up but the deceleration is small, acceleration caused by the control of the distance between two vehicles for making the distance between two vehicles to be a target value, is continued because of the time delay prior to the detection of deceleration. However, the control does not fit the driving sensation of the driver.
Furthermore, a problem is known that when a preceding vehicle on one's own lane where one's own vehicle is running, flashes on and off a winker and departs to another lane, a delay in acceleration is felt. This is because the acceleration is not performed until the preceding vehicle completely departs from one's own lane. When a preceding vehicle on another lane adjacent to one's own lane, flashes on and off a winker and comes into one's own lane, a delay in finishing of acceleration is felt. This is because the acceleration may be performed until the preceding vehicle comes into one's own lane. The above control does not fit the driving sensation of the driver.